Unicef and the WHO reveal that one in seven newborns weighs less than 2.5 kilos when they are born, mainly in poor countries. This low birth weight has an impact on their growth and health.
In 2015, 20.5 million children were born weighing less than 2.5 kilos, or about one in seven births worldwide. Nearly 90% of these births take place in low- and middle-income countries, particularly in South Asia and sub-Saharan Africa, reveals a new study published in the journal The Lancet Global Health.
Jointly carried out by the London School of Hygiene and Tropical Medicine, Unicef and the World Health Organization (WHO), this work highlights the consequences of this low birth weight on the future health of children. According to their authors, babies with low birth weight “are at greater risk of being stunted and of having health problems later on, including chronic conditions such as diabetes and cardiovascular disease”. They also have a higher risk of mortality. Indeed, more than 80% of the 2.5 million newborns who die each year in the world suffer from low birth weight, in particular because of their prematurity.
Strong regional disparities
To reach this conclusion, the researchers examined, from 2000 to 2015, national government databases and national surveys to estimate prevalence and track trends in underweight. In total, data was collected from more than 281 million births. However, the authors note that 47 countries (including 40 low- and middle-income countries that account for almost a quarter of all births worldwide) did not have sufficient data.
The results highlight notable differences between low- and middle-income countries and rich countries. In the latter, low birth weight is often associated with preterm birth. For Dr. Hanne Blencowe, who participated in the study, this prematurity can have multiple explanations, in particular “advanced age of the mother”, but also “tobacco consumption, unjustified recourse to cesarean section or treatments favoring fertility, which increase the likelihood of multiple births”.
One of the lowest low birth weight rates in 2015 was estimated in Sweden (2.4%). This figure is around 7% in some high-income countries. In detail: 8% in the United States, 7% in the United Kingdom, 6.5% in Australia or 5.7% in New Zealand.
One in two low birth weight births occurs in South Asia
The researchers also noted that the regions with the fastest progress are those with the highest number of babies with low birth weight. This is particularly the case for South Asia and sub-Saharan Africa, which recorded an annual decline of 1.4% and 1.1% respectively between 2000 and 2015.
Nevertheless, the total number of live births of low birth weight children has actually increased in sub-Saharan Africa, from 4.4 million to 5 million babies, mainly due to demographic trends (such as fertility and migrations). Similarly, South Asia still accounts for nearly half of the world’s low birth weight births, with an estimated 9.8 million in 2015.
“Low birth weight is a complex clinical entity comprised of intrauterine growth restriction and preterm birth,” analyzes Dr Mercedes de Onis of the WHO. “Therefore, reducing low birthweight requires understanding the underlying causes in a given country. For example, in South Asia, a large proportion of babies with low birthweight are born in term, but with intrauterine growth retardation, which is associated with maternal undernutrition, including maternal growth retardation.”
For international action against underweight
In 2012, WHO’s 195 member states pledged to reduce the prevalence of low birthweight by 30% by 2025, compared to 2012 levels. These estimates, which are the first of their kind , revealed that the prevalence of low birth weight worldwide decreased slightly from 17.5% in 2000 (22.9 million low birth weight live births) to 14.6% in 2015 (20.5 million).
However, the study indicates that at the current rate of progress – with a 1.2% annual decline in low birthweight rates between 2000 and 2015 – the world will be well below the annual rate of reduction of 2 .7% required to meet the WHO target of reducing prevalence by 30% between 2012 and 2025.
Hence the need “for further investment and action to accelerate progress, understanding and addressing the key drivers of low birthweight across the lifespan”, argue the authors of the report. ‘study. “Despite clear commitments, our estimates indicate that national governments are doing too little to reduce low birthweight. We have seen very little change in 15 years, even in high-income settings where the Low birth weight is often due to prematurity,” says Dr Blencowe. “Reaching the global nutrition goal of a 30% reduction in low birthweight by 2025 will require more than doubling the rate of progress.”
The study authors call for international action to ensure that all babies are weighed at birth, to improve clinical care and to promote public health action on the causes of low birthweight. to reduce mortality and disability.
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